Perforated crimpset can



P 26,1967 J. WINTER PERFORATED CRIMPSET CAN Filed Dec.

United States Patent 3,343,380 PERFORATED CRIMPSET CAN Juan Winter, Seaford, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del-, a corporation of Delaware Filed Dec. 8, 1965, Ser. No. 512,401 3 Claims. (Cl. 68-6) This invention relates generally to the production of textile fibers and, more particularly, to the steam treatment of crimped tow or staple in an oven or autoclave.

The practice of treating crimped fibers, in the form of either tow or staple, with steam is known. Oftentimes and for such purposes as setting or stabilizing the crimp, a can is filled with fibers and then located in an autoclave for the passage of steam therethrough. Although acceptable for the inended purpose, such a treatment can lead to nonuniformities in other respects. Specifically, it has been found that the dyeability of filaments or fibers varies with their location in a can during the crimp setting treatment.

According to this invention, dye uniformity is improved by steaming crimped textile fibers in a pressure vessel having facilities for the admission of steam and for the discharge of condensate through a steam trap. During treatment, the fibers are in an open top can having side walls and a bottom wall. The latter has a single opening located above and in communication with the steam trap. At least two area of which is a maximum adjacent the top and decreases to a minimum adjacent the bottom wall.

In the following descriptions, reference is made to the accompanying drawing in which FIGURE 1 is a partially schematic, perspective representation of a steam-treating over within which a carriage carrying four treatment cans has been positioned; and

FIG. 2 is an enlarged, perspective view of one of the cans shown in FIG. 1.

The apparatus embodiment illustrated in FIG. 1 includes an oven or autoclave 10 having a pair of pressuresealing doors 12, one of which has been omitted for purposes of clarity. A valved steam pipe 14 is connected to and discharges through the top of oven 10. Beneath the oven, there is a manifold 16, terminating in four upstanding pipe lengths 18, each of which carries a steam trap 20 and extends into oven 10. Manifold 16 discharges to a valved condensate return line 22. Oven 10 is also connected to a vacum system through valved pipe 24 and to atmosphere through valved pipe 26. A carriage 28 carrying four treatment cans 30 rides into oven 10 on tracks 32.

As shown in FIG. 2, each empty can 30 has an open top, side walls 34-37 and a bottom wall 38. Wall 38 is imperforate except for a drain hole 40 which communicates with a pipe length 18 through an identical hole in carriage 28 when the latter has been properly positioned in oven 10. Side walls 35, 36 are imperforate. Side walls 34, 37 are perforated in five specific zones which increase in area toward the top of can 30. The perforations in all zones are equidimensional and equally spaced in staggered rows.

In a use embodiment, can 30 is made from stainless steel and has a rectangular cross section with rectangular wallsv Walls 35, 36 are imperforate. Bottom wall 38 is also imperforate except for an oif-center drain hole 40 located adjacent wall 35. The perforations in walls 34, 37 are A-inch diameter holes arranged in horizontal rows with the hole centers staggered inch. Can 30 is 47 -inches high. In the lowest zone of perforations, the average distance of the holes from bottom wall 38 is 6.9 inches and there are seven rows of fifty-eight holes. The second zone has its center located 11.9 inches from bottom wall 38 and includes eight rows of holes. The middle zone has eleven rows of holes located an average distance of 17.3 inches from the bottom wall. In the fourth zone, there are thirteen rows of holes located an average distance of 22.2 inches from the bottom. The top zone has its center 32.2 inches from the bottom wall and includes nineteen rows of holes. A plot of the open area left by perforations in each zone against their average height shows that the available open area in any location is a linear function of the distance from bottom wall 38.

In operation, cans 30 are filled with crimped fibers 42 FIG. 1), either in the form of filamentary tow or staple, and placed on carriage 28. The four cans are aligned so that the two perforated sides of each are exposed and the two imperforate sides are in contact with the corresponding sides of adjacent cans. Carriage 28 is then rolled into autoclave 10 to a position such that drain holes 40 are each aligned with the open end of a pipe length 18. Doors 12 are closed to seal the autoclave. It is then possible to perform the steps of evacuating and pressurizing the oven with steam which flows through the filaments, condenses and exits through a trap 20.

With the previous usage of imperforate treatment cans in a flow-through system, steam condensed before the yarn got hot, Since the flow path was from top to bottom, distribution of condensate through the can was not uniform. When oven 10 is pressurized by opening the valve in pipe 14, steam is still directed primarily in at the top of the illustrated cans. However, metered amounts are also directed laterally in through the perforated zones in walls 34, 37. This leads to uniform heat and moisture distribution for all levels of fiber.

A comparative test was run on nylon filamentary tow wherein one batch was run with cans having all imperforate sides and a second test was run using the perforated cans described above for the use embodiment. Samples of tow were taken from near the top, from a level about /3 of the way down, from another level about /3 down and from the bottom of the cans. These were dyed to test the dye level uniformity. The aver-age standard deviation in dye level of thirty samples per can was reduced from 11.1 for the regular can having imperforate sides to 5.8 for the use embodiment having distributed perforations in two of its sides. Total average dye level difference between the top, /3 down, down and bottom levels was reduced from 22.3% for the cans with imperforate sides to 7.2% for the cans of this invention. This improved uniformity level is both acceptable and satisfactory.

In some instances, it may be advantageous to perforate three or four side walls of each can. Instead of the illustrated carriage and tracks, a lift or other suitable truck can be used for moving the cans to and from the oven. Other changes and modifications of a similar nature may be made without departing from the spirit of this invention which is therefore intended to be limited only by the scope of the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In combination with a fiber-steaming, pressure ves sel having facilities for the admission of steam and for the discharge of condensate through at least one steam trap,

an open top can having side walls and a bottom wall,

the Latter having an opening located above and communicating with said trap when the can has been positioned for steaming fibers therein, at least two side walls being provided with perforations.

2. The combination of claim 1 wherein the open area defined by said perforations is a maximum adjacent said top and decreases to a minimum adjacent said bottom wall.

3. The combination of claim 2 wherein said perforations are equidimensional and equally spaced in vertically spaced zones of staggered rows.

4 References Cited UNITED STATES PATENTS 5/1939 Wilson 6853 FOREIGN PATENTS 254,013 11/ 1912 Germany.

23,428 1898 Great Britain.

IRVING BUNEVICH, Primary Examiner. 

1. IN COMBINATION WITH A FIBER-STEAMING, PRESSURE VESSEL HAVING FACILITIES FOR THE ADMISSION OF STEAM AND FOR THE DISCHARGE OF CONDENSATE THROUGH AT LEAST ONE STEAM TRAP, AN OPEN TOP CAN HAVING SIDE WALLS AND A BOTTOM WALL, THE LATTER HAVING AN OPENING LOCATED ABOVE AND COM- 